Ccie

Back in 2021, I published a short post titled Welcome Back. In it, I mentioned that years prior, I had lost my entire original blog located at mellowd.co.uk/ccie during a botched server upgrade. That site had originally chronicled my journey toward my CCIE (#28448) and JNCIE-SP (#1134), along with deep dives into BGP, QoS, MPLS, and protocol internals. At the time of that 2021 post, I managed to manually piece back 13 articles using the Wayback Machine. But life got busy, and more than 20 detailed technical posts, along with dozens of network diagrams, hardware photos, and Wireshark captures, remained trapped in digital limbo. ...

I was forced to use a 3750G as a router yesterday for a WAN link that was only 70Mb. The LAN interfaces were all gig. The customer wanted to ensure that 30% of the bandwidth was available for EF marked packets. Everything else was to get 70% A lot of people have trouble with QoS on the 3750. This is mainly due to the tiny buffers, complexity, and the defaults it uses. ...

I know the title is quite a mouthful, but I did want to cover all the above in this post. Daniel asked me to check a few things as I have ready access to real switches. You learn in your studies that layer 2 control packets are ‘special’ – Special in the way that traffic going over the trunk between 2 switches does not follow the standard practice. Let’s use wireshark to see exactly what is going on in a bunch of scenarios. It’ll also give me the opportunity to do a bit of testing with SPAN and RSPAN. ...